DS/QPSK信号盲检测和估计算法的研究
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摘要
直接序列扩频(DSSS)信号由于其工作信噪比低、强抗干扰性、低截获率、能够抑制多径效应等优点,已经得到广泛应用,正日益取代常规通信而广泛应用于现代军事和商用通信系统中,如码分多址(CDMA)通信、全球定位系统(GPS)、测控、卫星链路和敌我识别等。因此,与之对应的直扩通信对抗技术也就成了通信对抗领域亟待解决的问题。直扩通信对抗包括直扩信号的盲检测、盲参数估计和扩频码序列恢复等内容。针对受强高斯噪声污染的DSSS/QPSK信号对抗技术的盲检测,盲参数估计及码序列恢复问题,本文主要内容如下:
1、分同步和非同步两种情况生成了DSSS基带信号,并对DSSS基带信号进行了QPSK调制,生成DSSS/QPSK调制信号。同时介绍了DSSS/QPSK信号的解调方案。
2、运用几种常用的检测方法对低信噪比下的DSSS/QPSK信号进行检测。检测方法包括功率谱检测法、时域相关检测方法、高阶统计量检测法等,文中对各种检测方法进行了计算机仿真,分析和比较。
3、在充分分析了DSSS/QPSK信号特点的基础上,分别采用平方倍频法,时域自相关法和延时相乘法对DSSS/QPSK信号的载波频率,码周期和码速率等参数进行估计。同时文中采用高阶累积量多参数估计方法对信号的参数进行估计。
4、总结和介绍了几种常用的码同步和恢复方法,包括特征值分解法,子空间跟踪法等,并进行了计算机仿真。基于子空间跟踪理论,本文将基于新息准则的快速子空间跟踪算法运用于直接序列扩频(DS/SS)信号的扩频码盲估计问题。计算机仿真表明这种算法降低了运算的复杂度和存储量,易于硬件实现,具有良好的收敛特性,能在较低的信噪比下快速准确的恢复出扩频序列。
5、建立了对DSSS/QPSK信号进行检测,参数估计和码序列恢复的联合处理系统,并对系统进行仿真和性能分析。
Direct sequence spread spectrum (DSSS) communication systems has been widely used in these years for its advantage of wide spectrum, low working Signal-to-Noise ratio (SNR), anti-interference, anti-multipath effect and capability of LPI and LPD. They are increasingly replacing conventional communication forms and obtaining extensively applications in modern military and commercial communication systems, for example, CDMA communication system, GPS , measuring and control system, satellite chain, identification of friend or foe and etc. Therefore, corresponding DSSS electronic counter technique becomes a big problem to solve in electronic warfare domain. DSSS electronic counter technique including blind detection, blind parameter estimation and spreading sequences estimation. For the issue of DSSS electronic counter technique of DSSS/QPSK signal damaged by strong additive white Gaussian noise (AWGN), the main research content in this dissertation as follow.
1、Both synchronous and asynchronous DSSS baseband signal are created and modulated to create DSSS/QPSK signal. At the same time, we introduce the demodulated method of DSSS/QPSK signal.
2、The characteristics of power spectrum, time-domain correlation and high-order statistics of the DSSS/QPSK signal are used to detect the signal. And the computer simulation is launched to analyze and compare the capability of different detection method.
3、Base on the adequate analysis of the characteristic of DSSS/QPSK signal, this dissertation mainly used carrier doubler method (CDM), auto-correlation method (ACM) and delay-and-multiply (DM) method to estimate the carrier frequency, the symbol period and the chip rate of DSSS/QPSK signal. At the same time, we introduced fourth-order cumulant 2-D slice method to realize multi-parameter estimate.
4、Several usual blind code synchronization and spreading sequences estimation methods, including matrix eigenvalue decomposition (EVD) and subspace tracking algorithms, are summed up and analyzed by computer simulations. Base upon the theoretics of subspace tracking, this dissertation introduce the algorithm based on fast subspace tracking by a Novel Information Criterion to solve the problem of blind estimation of DS/SS spreading sequence. Computer simulations show that this algorithm descends the storage consuming memory, is prone to hardware realization and has fast convergence properties, and this algorithm can estimate PN spreading sequence quickly and accurately at low SNR.
5、Finally, we established an associated system to process DSSS/QPSK signal including detection, parameter estimate and spreading sequences estimation. And the computer simulation was launched to analyze and compare the capability of different method combination.
1、分同步和非同步两种情况生成了DSSS基带信号,并对DSSS基带信号进行了QPSK调制,生成DSSS/QPSK调制信号。同时介绍了DSSS/QPSK信号的解调方案。
2、运用几种常用的检测方法对低信噪比下的DSSS/QPSK信号进行检测。检测方法包括功率谱检测法、时域相关检测方法、高阶统计量检测法等,文中对各种检测方法进行了计算机仿真,分析和比较。
3、在充分分析了DSSS/QPSK信号特点的基础上,分别采用平方倍频法,时域自相关法和延时相乘法对DSSS/QPSK信号的载波频率,码周期和码速率等参数进行估计。同时文中采用高阶累积量多参数估计方法对信号的参数进行估计。
4、总结和介绍了几种常用的码同步和恢复方法,包括特征值分解法,子空间跟踪法等,并进行了计算机仿真。基于子空间跟踪理论,本文将基于新息准则的快速子空间跟踪算法运用于直接序列扩频(DS/SS)信号的扩频码盲估计问题。计算机仿真表明这种算法降低了运算的复杂度和存储量,易于硬件实现,具有良好的收敛特性,能在较低的信噪比下快速准确的恢复出扩频序列。
5、建立了对DSSS/QPSK信号进行检测,参数估计和码序列恢复的联合处理系统,并对系统进行仿真和性能分析。
Direct sequence spread spectrum (DSSS) communication systems has been widely used in these years for its advantage of wide spectrum, low working Signal-to-Noise ratio (SNR), anti-interference, anti-multipath effect and capability of LPI and LPD. They are increasingly replacing conventional communication forms and obtaining extensively applications in modern military and commercial communication systems, for example, CDMA communication system, GPS , measuring and control system, satellite chain, identification of friend or foe and etc. Therefore, corresponding DSSS electronic counter technique becomes a big problem to solve in electronic warfare domain. DSSS electronic counter technique including blind detection, blind parameter estimation and spreading sequences estimation. For the issue of DSSS electronic counter technique of DSSS/QPSK signal damaged by strong additive white Gaussian noise (AWGN), the main research content in this dissertation as follow.
1、Both synchronous and asynchronous DSSS baseband signal are created and modulated to create DSSS/QPSK signal. At the same time, we introduce the demodulated method of DSSS/QPSK signal.
2、The characteristics of power spectrum, time-domain correlation and high-order statistics of the DSSS/QPSK signal are used to detect the signal. And the computer simulation is launched to analyze and compare the capability of different detection method.
3、Base on the adequate analysis of the characteristic of DSSS/QPSK signal, this dissertation mainly used carrier doubler method (CDM), auto-correlation method (ACM) and delay-and-multiply (DM) method to estimate the carrier frequency, the symbol period and the chip rate of DSSS/QPSK signal. At the same time, we introduced fourth-order cumulant 2-D slice method to realize multi-parameter estimate.
4、Several usual blind code synchronization and spreading sequences estimation methods, including matrix eigenvalue decomposition (EVD) and subspace tracking algorithms, are summed up and analyzed by computer simulations. Base upon the theoretics of subspace tracking, this dissertation introduce the algorithm based on fast subspace tracking by a Novel Information Criterion to solve the problem of blind estimation of DS/SS spreading sequence. Computer simulations show that this algorithm descends the storage consuming memory, is prone to hardware realization and has fast convergence properties, and this algorithm can estimate PN spreading sequence quickly and accurately at low SNR.
5、Finally, we established an associated system to process DSSS/QPSK signal including detection, parameter estimate and spreading sequences estimation. And the computer simulation was launched to analyze and compare the capability of different method combination.
引文
[1] 查光明,熊贤祚.扩频通信.西安电子科技大学出版社,1990.12, 1-198
[2] Keenan, R.Kenneth. Comlink: A Communication/EW Analytical and Modeling Tool. IEEE Electronics and Aerospace Systems Convention, EASCON Rec IEEE Electron and Aerosp Syst Conv, 1980: 244-252
[3] 袁孝康.扩频与电子对抗. 航天电子对抗,1995(3), 31-38
[4] 熊群力. 通信对抗的未来发展. 通信对抗,1996(2)
[5] 李承恕,赵荣黎编著. 扩展频谱通信. 人民邮电出版社,1993
[6] 朱晓霞,陆明泉,肖先赐. 通信信号细微特征分析. 电子对抗,1995(3): 2-11
[7] H. Urkowitz. Energy Detection of Unknown Deterministic Signal. IEEE Proc,1967(55): 523-531
[8] Dillard, R.A. Detectability of Spread-Spectrum Signals. IEEE Trans. on AES. July 1979, 15
[9] Polydoros, A. and Weber, C.L. Detection Performance Considerations for Direct-Sequence and Time-Hopping LPI Waveforms. IEEE Journal on SAIC, Vol. 3, No. 5, Sept., 1985 pp: 727-744.
[10] French C A, Gardner W A. Spread-spectrum despreading without the code. IEEE Transactions On Communications, 1986,34(4):404-407
[11] Kuehls J F, Geraniotis E. Presence Detection of Binary-Phase-Shift-Keyed and Direct-Sequence Spread-Spectrum Signals Using a Prefilter-Delay-and-Multiply Device. IEEE journal on Selected Areas in Communications, 1990,8(5):915-933
[12] Reed, D.E. and Wickert, M.A. Minimization of Detection of Symbol-Rate Spectral Lines by Delay and Multiply Receivers. IEEE Trans. on Communications, January, 1988, 36(1): 118-120.
[13] Reed, D.E. and Wickert, M.A. A Performance of Optimum and Sub-Optimun Receiver Structure for Rate-Line Detection of Digitally Modulated Carriers. IEEE Region 5 Conference, 1988: Spanning the Peaks of Electrotechnology, 1988: 177-181.
[14] Spooner, C.M. and Gardner, W. A. Exploitation of Higher-Order Cyclostationarity for Weak-Signal Detection and Time-Delay Estimation. IEEE 1992.
[15] Lu Minquan and Xiao Xianci. Detection of DS/SS Signal Using Fourth-Order spectrum.Proceeding of ICSP'93.
[16] Gouda, M. Adams, E.R. Hill, P.C.J. Detection & discrimination of covert DS/SS signals using triple correlation. Radio Science Conference, 1998. NRSC '98. Proceedings of the Fifteenth National, 1998: C35/1 -C35/6.
[17] Gardner, W.A. Measurement of Spectral Correlation. IEEE Trans on ASSP, 1986, 34(5): 1111-1123
[18] Gardner, W.A. and Spooner, C.M. Signal Interception: Performance Advantages of Cyclic-Feature Detectors. IEEE Trans. on Communications, January, 1992, 40(1): 149-159
[19] D.A.Hill, J.B.Bodie. Carrier detection of unbalanced QPSK direct sequence signals. MILCOM 1999, 1999,1: 437-441
[20] Douglas A.Hill, John B.Bodie. Carrier detection of PSK signals. IEEE Trans. Commun, 2001,49(3): 487-496
[21] Burel. Gilles, Bouder.C, Berder.O. Detection of direct sequence spread spectrum transmissions without prior knowledge. Conference Record IEEE Global Telecommunications Conference, 2001, 1: 236-239
[22] Zhenhui Shen, Bin Tang. Multiple parameters estimation simultaneously for DS-SS-BPSK signal based on fourth-order cumulant 2D slice. Communications, Circuits and Systems, 2004. ICCCAS 2004. 2004 International Conference on, June 2004,2: 867-870
[23] 沈振惠, 唐斌等. 基于四阶统计 2-D 切片的直扩信号多参数估计. 信号处理, 2005(3), 304-306
[24] Yingwei Yao, Poor H V. EM-based blind demodulation of synchronous CDMA. IEEE International Symposium on Spread Spectrum Techniques and Applications, 2000, 2: 738-742
[25] French C A, Gardener W A. Spread-spectrum despreading without the code. IEEE Transactions on Communications, 1986, 34(4): 404-407
[26] 杨小牛. 直接序列(DS)扩频码的截获与干扰技术初探. 通信对抗,1991, (3):78-83
[27] 谈满堂,朱德君. 谱相关理论用于直接序列扩谱信号的检测与估计. 电子对抗,1995,(4):53-59
[28] Hill P C J, Ridley M E. Blind Estimation of direct-sequence spread spectrum M-sequence chip codes. IEEE International Symposium on Spread Spectrum Techniques and Applications, 2000, 1: 305-309
[29] Bouder C, Azou S, Burel G. Blind estimation of the pseudo-random sequence of a direct sequence spread spectrum signal. IEEE-MILCOM, 2000, 2(10): 967-970
[30] Bouder C, Azou S, Burel G. A robust synchronization procedure for blind estimation of the symbol period and the timing offset in spread spectrum transmissions. Spread Spectrum Techniques and Applications, 2002 IEEE Seventh International Symposium on, 2002, 1: 238 – 241
[31] Bouder C, Azou S, Burel G. Performance analysis of a spreading sequence estimator for spread spectrum transmissions. Journal of The Franklin Institute, 2004, 341(7): 595-614
[32] 朱孝武,唐斌. 基于 DS-SS 信号相位特性的参数估计. 电子与信息学报, 2005, 27(9):1425-1428
[33] 张天骐,周正中,郭宗祥. 一种 DS/SS 信号 PN 码序列估计的神经网络方法. 信号处理,2001,17(6):533-537
[34] 张 天 骐 , 周 正 中 . 直 扩 信 号 的 谱 检 测 和 神 经 网 络 估 计 . 系 统 工 程 与 电 子 技术,2001,23(12):12-15
[35] Afshin Haghighat, Soleymani M R. A MUSIC-based algorithm for spreading sequence discovery in multiuser DS-CDMA. IEEE Vehicular Technology Conference, 2003, 58(2): 978-981
[36] Afshin Haghighat, Soleymani M R. Blind spreading sequence discovery for DS-CDMA signal interception. IEEE Military Communications Conference MILCOM, 2003, 2: 1115-1119
[37] Robert C D. Spread spectrum systems. New York: John Wiley & Sons, 1984, 15-79
[38] 潘士先.谱估计和自适应滤波.北京:北京航空航天大学出版社,1991,114-166
[39] Welch P D. The use of fast fourier transform for the estimation of power spectra: a method based on time averaging over short, modified periodograms. IEEE Transactions on Audio electroacoustics, 1967,15(2):70-73
[40] 张贤达.现代信号处理.北京:清华大学出版社,2002,263-273
[41] 曹志刚,钱亚生. 现代通信原理. 清华大学出版社,1992, 207-213
[42] 游凌. DS 直扩信号参数隐周期特征分析法. 信号处理,2000, 16: 8-14
[43] 刘基南,袁亮. 一种直扩信号伪码速率的快速检测方法. 现代防御技术. 2005,33(1): 62-64
[44] Bouder C, Azou S, Burel G. Blind estimation of the pseudo-random sequence of a direct sequence spread spectrum signal. IEEE-MILCOM, 2000, 2(10): 967-970
[45] 张贤达. 矩阵分析与应用. 北京:清华大学出版社,2004,255-653
[46] Haykin S. Neural networks: a comprehensive foundation. Beijing: Tsinghua University Press, 2001, 1-207
[47] Yang Bin. Projection approximation subspace tracking. IEEE Transactions on Signal Processing,1995, 43(1): 95-107
[48] Yang Bin. Convergence analysis of the subspace tracking algorithms PAST and PASTd. IEEE International Conference on Acoustics, Speech and Signal Processing – Proceedings, 1996, 3: 1759-1762
[49] Yang Bin. Asymptotic convergence analysis of the projection approximation subspace tracking algorithms. Signal Processing, 1996, 50(1): 123-136
[50] Yongfeng Miao, Yingbo Hua. Fast subspace tracking by a novel information criterion. Conference Record of the Asilomar Conference on Signals, Systems & Computers, 1997, 2: 1312-1316
[51] Yongfeng Miao, Yingbo Hua. Fast subspace tracking and neural network learning by a novel information criterion. IEEE International Conference on Acoustics, Speech and Signal Processing, 2003, 2: 1197-1200
[2] Keenan, R.Kenneth. Comlink: A Communication/EW Analytical and Modeling Tool. IEEE Electronics and Aerospace Systems Convention, EASCON Rec IEEE Electron and Aerosp Syst Conv, 1980: 244-252
[3] 袁孝康.扩频与电子对抗. 航天电子对抗,1995(3), 31-38
[4] 熊群力. 通信对抗的未来发展. 通信对抗,1996(2)
[5] 李承恕,赵荣黎编著. 扩展频谱通信. 人民邮电出版社,1993
[6] 朱晓霞,陆明泉,肖先赐. 通信信号细微特征分析. 电子对抗,1995(3): 2-11
[7] H. Urkowitz. Energy Detection of Unknown Deterministic Signal. IEEE Proc,1967(55): 523-531
[8] Dillard, R.A. Detectability of Spread-Spectrum Signals. IEEE Trans. on AES. July 1979, 15
[9] Polydoros, A. and Weber, C.L. Detection Performance Considerations for Direct-Sequence and Time-Hopping LPI Waveforms. IEEE Journal on SAIC, Vol. 3, No. 5, Sept., 1985 pp: 727-744.
[10] French C A, Gardner W A. Spread-spectrum despreading without the code. IEEE Transactions On Communications, 1986,34(4):404-407
[11] Kuehls J F, Geraniotis E. Presence Detection of Binary-Phase-Shift-Keyed and Direct-Sequence Spread-Spectrum Signals Using a Prefilter-Delay-and-Multiply Device. IEEE journal on Selected Areas in Communications, 1990,8(5):915-933
[12] Reed, D.E. and Wickert, M.A. Minimization of Detection of Symbol-Rate Spectral Lines by Delay and Multiply Receivers. IEEE Trans. on Communications, January, 1988, 36(1): 118-120.
[13] Reed, D.E. and Wickert, M.A. A Performance of Optimum and Sub-Optimun Receiver Structure for Rate-Line Detection of Digitally Modulated Carriers. IEEE Region 5 Conference, 1988: Spanning the Peaks of Electrotechnology, 1988: 177-181.
[14] Spooner, C.M. and Gardner, W. A. Exploitation of Higher-Order Cyclostationarity for Weak-Signal Detection and Time-Delay Estimation. IEEE 1992.
[15] Lu Minquan and Xiao Xianci. Detection of DS/SS Signal Using Fourth-Order spectrum.Proceeding of ICSP'93.
[16] Gouda, M. Adams, E.R. Hill, P.C.J. Detection & discrimination of covert DS/SS signals using triple correlation. Radio Science Conference, 1998. NRSC '98. Proceedings of the Fifteenth National, 1998: C35/1 -C35/6.
[17] Gardner, W.A. Measurement of Spectral Correlation. IEEE Trans on ASSP, 1986, 34(5): 1111-1123
[18] Gardner, W.A. and Spooner, C.M. Signal Interception: Performance Advantages of Cyclic-Feature Detectors. IEEE Trans. on Communications, January, 1992, 40(1): 149-159
[19] D.A.Hill, J.B.Bodie. Carrier detection of unbalanced QPSK direct sequence signals. MILCOM 1999, 1999,1: 437-441
[20] Douglas A.Hill, John B.Bodie. Carrier detection of PSK signals. IEEE Trans. Commun, 2001,49(3): 487-496
[21] Burel. Gilles, Bouder.C, Berder.O. Detection of direct sequence spread spectrum transmissions without prior knowledge. Conference Record IEEE Global Telecommunications Conference, 2001, 1: 236-239
[22] Zhenhui Shen, Bin Tang. Multiple parameters estimation simultaneously for DS-SS-BPSK signal based on fourth-order cumulant 2D slice. Communications, Circuits and Systems, 2004. ICCCAS 2004. 2004 International Conference on, June 2004,2: 867-870
[23] 沈振惠, 唐斌等. 基于四阶统计 2-D 切片的直扩信号多参数估计. 信号处理, 2005(3), 304-306
[24] Yingwei Yao, Poor H V. EM-based blind demodulation of synchronous CDMA. IEEE International Symposium on Spread Spectrum Techniques and Applications, 2000, 2: 738-742
[25] French C A, Gardener W A. Spread-spectrum despreading without the code. IEEE Transactions on Communications, 1986, 34(4): 404-407
[26] 杨小牛. 直接序列(DS)扩频码的截获与干扰技术初探. 通信对抗,1991, (3):78-83
[27] 谈满堂,朱德君. 谱相关理论用于直接序列扩谱信号的检测与估计. 电子对抗,1995,(4):53-59
[28] Hill P C J, Ridley M E. Blind Estimation of direct-sequence spread spectrum M-sequence chip codes. IEEE International Symposium on Spread Spectrum Techniques and Applications, 2000, 1: 305-309
[29] Bouder C, Azou S, Burel G. Blind estimation of the pseudo-random sequence of a direct sequence spread spectrum signal. IEEE-MILCOM, 2000, 2(10): 967-970
[30] Bouder C, Azou S, Burel G. A robust synchronization procedure for blind estimation of the symbol period and the timing offset in spread spectrum transmissions. Spread Spectrum Techniques and Applications, 2002 IEEE Seventh International Symposium on, 2002, 1: 238 – 241
[31] Bouder C, Azou S, Burel G. Performance analysis of a spreading sequence estimator for spread spectrum transmissions. Journal of The Franklin Institute, 2004, 341(7): 595-614
[32] 朱孝武,唐斌. 基于 DS-SS 信号相位特性的参数估计. 电子与信息学报, 2005, 27(9):1425-1428
[33] 张天骐,周正中,郭宗祥. 一种 DS/SS 信号 PN 码序列估计的神经网络方法. 信号处理,2001,17(6):533-537
[34] 张 天 骐 , 周 正 中 . 直 扩 信 号 的 谱 检 测 和 神 经 网 络 估 计 . 系 统 工 程 与 电 子 技术,2001,23(12):12-15
[35] Afshin Haghighat, Soleymani M R. A MUSIC-based algorithm for spreading sequence discovery in multiuser DS-CDMA. IEEE Vehicular Technology Conference, 2003, 58(2): 978-981
[36] Afshin Haghighat, Soleymani M R. Blind spreading sequence discovery for DS-CDMA signal interception. IEEE Military Communications Conference MILCOM, 2003, 2: 1115-1119
[37] Robert C D. Spread spectrum systems. New York: John Wiley & Sons, 1984, 15-79
[38] 潘士先.谱估计和自适应滤波.北京:北京航空航天大学出版社,1991,114-166
[39] Welch P D. The use of fast fourier transform for the estimation of power spectra: a method based on time averaging over short, modified periodograms. IEEE Transactions on Audio electroacoustics, 1967,15(2):70-73
[40] 张贤达.现代信号处理.北京:清华大学出版社,2002,263-273
[41] 曹志刚,钱亚生. 现代通信原理. 清华大学出版社,1992, 207-213
[42] 游凌. DS 直扩信号参数隐周期特征分析法. 信号处理,2000, 16: 8-14
[43] 刘基南,袁亮. 一种直扩信号伪码速率的快速检测方法. 现代防御技术. 2005,33(1): 62-64
[44] Bouder C, Azou S, Burel G. Blind estimation of the pseudo-random sequence of a direct sequence spread spectrum signal. IEEE-MILCOM, 2000, 2(10): 967-970
[45] 张贤达. 矩阵分析与应用. 北京:清华大学出版社,2004,255-653
[46] Haykin S. Neural networks: a comprehensive foundation. Beijing: Tsinghua University Press, 2001, 1-207
[47] Yang Bin. Projection approximation subspace tracking. IEEE Transactions on Signal Processing,1995, 43(1): 95-107
[48] Yang Bin. Convergence analysis of the subspace tracking algorithms PAST and PASTd. IEEE International Conference on Acoustics, Speech and Signal Processing – Proceedings, 1996, 3: 1759-1762
[49] Yang Bin. Asymptotic convergence analysis of the projection approximation subspace tracking algorithms. Signal Processing, 1996, 50(1): 123-136
[50] Yongfeng Miao, Yingbo Hua. Fast subspace tracking by a novel information criterion. Conference Record of the Asilomar Conference on Signals, Systems & Computers, 1997, 2: 1312-1316
[51] Yongfeng Miao, Yingbo Hua. Fast subspace tracking and neural network learning by a novel information criterion. IEEE International Conference on Acoustics, Speech and Signal Processing, 2003, 2: 1197-1200